Editor’s note: This post is part of an ongoing series of short Ham Radio 101 articles from OnAllBands addressing the basics of amateur radio as a service to aspiring and new hams.
From contesting to Morse code, ham radio operators are never short on things to do or communication activities to learn about.
One of those activities is moonbouncing, and while it sounds like a spoof of the popular James Bond movie “Moonraker” (also the name of a valued vendor at DXEngineering.com), how it’s done and its origins are no joke.
Moonbouncing, also called Earth-Moon-Earth (EME) communication, is when a radio signal is sent from Earth and reflected off the surface of the moon back down to Earth. It’s a difficult technique that almost always requires a high-gain antenna and sensitive receiver because of how weak the signals are on their return trip to our planet.
But while still challenging, OnAllBands blogger Sean Kutzko, KX9X, points out in his article, “Beyond Your Local Repeater: 15 Things to Do with a Technician License,” that EME has become significantly easier thanks to the WSJT suite created by Joe Taylor, K1JT. The software allows decoding of digitally transmitted signals many decibels below the noise floor.
Moonbounce is primarily used to communicate over great distances commonly using the 2M, 70cm, and 23cm bands—mostly through CW and Digital modes.
The practice was first theorized in 1940 by W.J. Bray of the British General Post Office. He believed that with available microwave transmission powers and low-noise receivers, it would be possible to send microwave signals from Earth and reflect them off the moon. German experiments in 1943 showed it was possible.
The first successful attempt at moonbouncing a human’s voice was done in 1954 at the Naval Research Laboratory (NRL—now the Naval Surface Warfare Center) in Stump Neck, Maryland. The idea was to use this method of sending signals to transmit secure messages with Navy ships.
In 1961, Chief of Naval Operations Admiral George W. Anderson and Dr. R.M. Page, director of research for the NRL, sent a message from Stump Neck to the USS Oxford in the Atlantic Ocean, approximately 1,500 miles from Maryland. It was the first successful ground-to-ship transmission using moonbouncing, according to the National Air and Space Museum.
Amateur radio enthusiasts, including the team of active operators at DX Engineering, enjoy the challenges of making moonbounce contacts. In 2009, hams celebrated the 40th anniversary of the Apollo 11 moon landing via World Moon Bounce Day, which was hosted by Echoes of Apollo. The ARRL holds an annual EME contest, which challenges amateurs to work as many stations as possible via the Earth-Moon-Earth path. DXpeditioners, like the TX7N team activating Marquesas in January 2025, have encouraged DXers to put this island group in their logs by making EME QSOs.
It’s even showed up in popular culture. Composer Pauline Oliveros used moonbounce in her 1987 composition “Echoes from the Moon”.
More recently, German musician Hainbach used the technique to create an audio plug-in to reproduce the effect for other musicians.
If you’re thinking about taking on the rewarding task of attempting a moonbounce, visit DX Engineering for the gear—and advice—to help make it possible.
